Displaying cutting force of soft tissue using MR fluid for surgical simulators

For improving surgical techniques of novice surgeons or preoperative planning, development of practical surgical simulators utilizing virtual reality technology have been expected in the medical field. During surgery, a surgeon uses a variety of surgical instruments. Therefore, a haptic interface should be able to display reaction force through various surgical instruments. Based on this concept, a novel encountered-type haptic interface using MR (Magneto-Rheological) fluid for surgical simulators was developed. In this paper, a force feedback control scheme using a force sensor mounted on a MR fluid container is proposed. By using this scheme, performance of frequency response and effectiveness of the proposed control scheme are evaluated. In this frequency response experiment, it is evaluated that a force bandwidth of the closed-loop controller for the fluid is 200 [Hz] and it has sufficient performance to replicate vibratory cutting force of soft tissue. Moreover, by moving the container, the proposed scheme can display force based on reference force while the knife stops. Therefore, the proposed method can replicate cutting force of soft tissue correctly, and has sufficient performance to be used as surgical simulators.